87 Performance Tune vs Stock Tune

[BC_Leadfoot]

When my preditor builds a tune off of my stock tune, what changes does it make? Is there a set value for fuel and spark that it sets determined by the value of the stock? How expensive is it to get a tune custom built for my truck?

[06MonteSS]

some of the fueling may be changed, fans, PE/WOT settings, TM, KR settings, etc etc... but the timing in the 87 tune is not changed from the stock settings, since you're only running 87 octane gas anyway...